Hard to beleive a great horned owl could do what you described maybe a raccoon they can open just about anything that is why we have to make sure what kind of locks and bolts we use to keep out birds safe in their houses. i am not disputing what you aresaying just having a hard time thinking of an owl being able to work a rachet strap off and get the duck.
I am very sorry, I hope you get some ducklings from these eggs.
I am very sorry, I hope you get some ducklings from these eggs.